GetLHXYFromTPA()

procedure GetLHXYFromTPA(TPA: TPointArray; var LX, LY, HX, HY: Integer);
var
  h, i: Integer;
  mn, mx: TPoint;
begin
  mn := Point(-1, -1);
  mx := Point(-1, -1);
  h := High(TPA);
  if (h > -1) then
  begin
    mn := Point(TPA[0].X, TPA[0].Y);
    mx := Point(TPA[0].X, TPA[0].Y);
    if (h > 0) then
    for i := 1 to h do
    begin
      mn.X := Min(mn.X, TPA[i].X);
      mn.Y := Min(mn.Y, TPA[i].Y);
      mx.X := Max(mx.X, TPA[i].X);
      mx.Y := Max(mx.Y, TPA[i].Y);
    end;
  end;
  LX := mn.X;
  LY := mn.Y;
  HX := mx.X;
  HY := mx.Y;
end;

var
  lowestX, lowestY, highestX, highestY: Integer;
  TPA: TPointArray;

begin
  ClearDebug;
  TPA := TPAFromCircle(50, 50, 10);
  GetLHXYFromTPA(TPA, lowestX, lowestY, highestX, highestY);
  WriteLn('Lowest X' + IntToStr(lowestX));
  WriteLn('Lowest Y' + IntToStr(lowestY));
  WriteLn('Highest X' + IntToStr(highestX));
  WriteLn('Highest Y' + IntToStr(highestY));
end.